Aluminum and its
alloys are divided into two broad classes,
castings and wrought (mechanically worked
products). The latter is sub-divided into
heat-treatable and non-heat-treatable alloys,
and into various forms produced by mechanical
working.

For greatest
strength. Heat treatable. Other alloying
elements such as copper, magnesium,
chromium and zirconium may be specified.

8xxx

Tin,
Lithium & Other elements.

Effects
vary.

9xxx

N/A

(This series
is unused presently.)

Casting
Alloys

Series

Main
Alloy

Alloy
Notes

1xx.x

None
(99% alum.)

Unalloyed aluminum.

2xx.x

Copper

Used extensively for
applications where excellent strength
and hardness at high temperatures are
required. Heavy-duty pistons; motorcycle,
diesel and aircraft pistons; aircraft
generator housings; and air-cooled cylinder
heads are typical applications.

3xx.x

Silicon

Other alloying elements
such as copper and magnesium are specified.
Typical applications are airframe castings,
machine parts, truck chassis parts,
aircraft and missile components, and
structural parts requiring high strength.

4xx.x

Silicon

5xx.x

Magnesium

Alloys possess a high
and stable combination of strength,
shock resistance and ductility. It is
ideally suited for parts in instruments
and computing devices where dimensional
stability is of major importance.

6xx.x

N/A

(This series is unused
presently.)

7xx.x

Zinc

Employed when a combination
of good mechanical properties without
heat treatment is needed. It also shows
good shock and corrosion resistance
and good machinability and dimensional
stability.